1. Field of the Invention
The present invention relates to a seat with a walk-in mechanism, which is so designed that the seat may be moved forwardly to a walk-in position where a passenger can smoothly get in a vehicle behind the seat in order to climb onto or descend from a rear seat or the like. More particularly, the invention is directed to a structure of such seat with walk-in mechanism wherein a biasing force of spring element is used to forcibly cause forward sliding movement of the seat to the walk-in position in conjunction with forward inclination of a seat back of the seat.
2. Description of Prior Art
Among seats with walk-in mechanism (the so-called “walk-in seat”), there has been known a seat with walk-in mechanism of the type using a spring element. Such walk-in seat is used as a front seat in most cases. For instance, according to a seat of this kind disclosed in the Japanese Laid-Open Patent Publication No. 2004-122798, a spring element is mounted in a seat slide device provided beneath a seat cushion of the seat, and, upon forward inclination of a seat back connected via a reclining device with the seat cushion, a lock mechanism is operated to unlock the reclining device and simultaneously the seat is slidingly moved along the slide device forwardly by a biasing force of the spring element.
In this walk-in mechanism, therefore, the seat is moved forwardly by the biasing force of spring element. That is, the spring element is required to have a biasing force enough to cause the sliding movement of the seat, considering a weight of the seat itself and a certain resistance in the slide rail device against the sliding movement of seat.
In particular, in the case where a backwardly slant support base member is provided between the seat and a floor of vehicle to incline both seat and seat slide device upwardly relative to the backward end portions of the seat and seat slide device, a considerably increased biasing force is required in the spring element in addition to the abovementioned factors.
Certainly, the use of such spring element with a highly increased biasing force is effective in causing forward sliding movement of the seat along the upwardly sloped support base member to a given walk-in position. But, in that case, a considerable force against such strong biasing force is required to a user who will move back the seat that has been moved to the walk-in position towards a normal use position. Hence, this improvement leaves a problem in terms of an undesired labor on the user's side, which will eventually result in a poor operationability of both walk-in mechanism and seat.